The Development of a System to Suppress and Extinguish Fully Developed Coal Dust Explosions: Progress Report
The Development of a System to Suppress and Extinguish Fully Developed Coal Dust Explosions: Progress Report

Author: L. D. Johnson

Publisher:

Published: 1973

Total Pages: 140

ISBN-13:

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INGUISHERS, FLAME PROPAGATION, POTASSIUM COMPOUNDS, CARBONATES, PRESSURE*COAL DUST, COAL MINES, SYSTEMS ANALYSIS, MINE SAFETY, POTASSIUM CARBONATESA program for the Bureau of Mines to develop a system to suppress coal mine dust explosives has achieved certain notable results at the end of the first year. After extensive study of coal dust explosion phenomena a project plan was developed, a test facility built and several suppression devices tested. The facility is a 4.5 foot diameter shock tube, 317 feet in length, and to date 53 tests have been carried out with methane-air and methane/coal dust-air as the explosive mixtures. Suppression of slowly propagating (up to 300 ft/sec) flame fronts has been successfully carried out on two tests using the dry chemical extinguishing agent Purple K. Delivery of the material directly into the flame front seems to be required if effective suppression is to be accomplished. (Author).

Research on the Suppression of Coal Dust Explosions by Water Barriers
Research on the Suppression of Coal Dust Explosions by Water Barriers

Author: J-Z Lu

Publisher:

Published: 1987

Total Pages: 6

ISBN-13:

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Chongqing Coal Research Institute has been conducting experimental research on water barriers to determine their feasibility for installation in underground coal mines in China. The performance tests of 40- and 80-L tubs indicate that when the dynamic wind pressure is equal to or more than 0.16 kg/cm2 they rupture and water disperses to form a spray cloud, which lasts for 75 to 150 ms. The cloud is 7 m long and spreads about 4 m wide. For extinguishing coal dust explosions, water barrier tests were conducted in our experimental gallery (896-m total length and 7.2-m2 cross section). The test results have shown that barriers can effectively suppress coal dust explosions propagating at speeds of 80 to over 700 m/s. It was found that a delay time of from 2 to 1100 ms between barrier operation and flame arrival does not reduce their effectiveness. However, when the flame propagates slowly and the explosion pressure does not develop sufficiently, the barrier can be ineffective. Further research is necessary to improve the tub materials, their design, and their configuration.